Tamoxifen

Mechanism :

It is an anti-estrogenic that blocks the actions of estrogens on the estrogen receptors. It is used in the treatment of gynaecomastia and breast cancer.

Indication :

McCune-Albright Syndrome
Precocious puberty

Contraindications :

History of blood clots in your veins or your lungs;

If also taking a blood thinner such as warfarin (Coumadin);

Hypersensitivity.

Dosing :

McCune-Albright Syndrome and precocious puberty:

2-10 years: 20 mg once a day. The duration of treatment is up to 12 months.

Adverse Effect :

Vomiting, menstrual irregularities, thrombocytopenia and visual disturbances.

Interaction :

Cimetidine: Cimetidine may decrease the therapeutic effect of Tamoxifen by decreasing the production of active metabolites. Consider alternate therapy.
Desipramine: Desipramine may decrease the therapeutic effect of Tamoxifen by decreasing the production of active metabolites. Consider alternate therapy.
Fluconazole: Fluconazole may reduce clearance rate of Tamoxifen. Monitor for changes in therapeutic/adverse effects of Tamoxifen if Fluconazole is initiated, discontinued or dose changed.
Gemfibrozil: Gemfibrozil may reduce clearance rate of Tamoxifen. Monitor for changes in therapeutic/adverse effects of Tamoxifen if Gemfibrozil is initiated, discontinued or dose changed.

Renal Dose :

Dose in Renal Impairment GFR (mL/min)

20-50	Dose as in normal renal function
10-20	Dose as in normal renal function
<10	Dose as in normal renal function

Dose in Patients undergoing Renal Replacement Therapies

CAPD	Unknown dialysability. Dose as in normal renal function
HD	Unknown dialysability. Dose as in normal renal function
HDF/High flux	Unknown dialysability. Dose as in normal renal function
CAV/VVHD	Unknown dialysability. Dose as in normal renal function

Hepatic Dose :

No dose adjustment recommended. Monitor liver function periodically as hepatocellular carcinoma, elevated liver function tests and other hepatic abnormalities have been reported with patients taking tamoxifen.